Authorities said a bullet struck the unidentified man in his arm after he dropped the weapon Tuesday. He was among several armed residents guarding the Save Yourself Survival and Tactical Gear store in Oktaha, a town of 390 about 65 miles southeast of Tulsa.

The Council on American-Islamic Relations says the Oklahoma business and ones in several other states have declared themselves "Muslim-free," and the organization has asked the U.S. Department of Justice to investigate some for possible civil rights violations.

The armed locals said they began guarding the Oklahoma shop after owners claimed they received death threats over the sign. The owners didn't immediately return a message seeking comment about the alleged threats.

"The way they were holding their weapons, with the fingers on the triggers, you can tell a couple of these gentlemen have no idea about weapons safety. It's like the Clampetts have come to town," Muskogee County Sheriff Charles Pearson told the online news outlet muskogeenow.com, comparing the armed men to the family in the TV series "The Beverly Hillbillies."

An operator of the store's Facebook page directed reporters to a statement posted late Tuesday that called the shooting "an unfortunate accident." The statement claimed the man who shot himself came over to the shop to help fix a door in the office "and, as he bent over, his weapon fell from a malfunctioning chest holster and went off when it hit the floor."

"As far as the need to send armed citizens to protect this business, we think it's really a shame they can't rely on local law enforcement," said Veronica Laizure, civil rights director for the Oklahoma chapter of the Council on American-Islamic Relations.